Steering Control Device Neutral Position Offset
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Solution Overview
Problem
Conventional steering systems cause a large steering load on drivers when correcting the vehicle's position within a lane, as the steering torque neutral position coincides with the steering angle neutral position, leading to inverted torque signs and directional control switches.
Innovation Solution
A steering control device that mechanically uncouples the steering unit from the turning unit, using a steering reaction force characteristic where larger self-aligning torque results in larger steering reaction force, and offsetting this characteristic to prevent torque sign inversion during corrective steering, thereby reducing driver effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the steering angle neutral position and steering torque neutral position coincide, then the steering system provides straightforward neutral positioning, but the driver experiences large steering load during corrective steering due to torque sign inversion
Solution Approach 1:
The patent applies parameter changes by offsetting the steering torque neutral position relative to the steering angle neutral position. Specifically, the steering torque neutral position is set at a steering angle that corresponds to a predetermined offset amount from the steering angle neutral position. This parameter modification prevents torque sign inversion during corrective steering, thereby reducing steering load on the driver without requiring complex additional mechanisms.
2Reliability
If the steering torque neutral position is offset from the steering angle neutral position, then torque sign inversion is suppressed during corrective steering, but the steering system becomes more complex
Solution Approach 1:
The patent implements parameter changes by establishing a predetermined offset relationship between the steering angle neutral position and the steering torque neutral position. The steering torque neutral position is defined at a specific steering angle offset from the steering angle neutral position, which ensures consistent torque sign during corrective steering maneuvers. This parameter-based solution maintains reliability while avoiding overly complex system architecture.
3Ease of operation
If the steering reaction force characteristic is offset to increase absolute value of steering reaction force, then the steering torque neutral position is shifted to reduce torque inversion, but the steering force characteristic changes
Solution Approach 1:
The patent applies parameter changes by offsetting the steering reaction force characteristic curve. Specifically, the steering reaction force characteristic is shifted in a direction that increases the absolute value of the steering reaction force at the steering torque neutral position. This parameter modification shifts the neutral position and prevents torque sign inversion, while the change in force characteristic is controlled and predetermined to maintain steering control consistency.
Data Source
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AI summary
The turning amount of a turning unit (2) is controlled according to the steering amount of a steering unit (1) mechanically uncoupled from the turning unit (2). A steering reaction force characteristic such that the larger the self-aligning torque, the larger the steering reaction force is set on coordinates with the self-aligning torque and the steering reaction force as coordinate axes. When a steering reaction force corresponding to the self-aligning torque is applied to the steering unit (1) based on the steering reaction force characteristic, the steering reaction force characteristic is offset on the coordinates in such a direction that the larger the integral value of a yaw angle, the larger the absolute value of the steering reaction force, the yaw angle being an angle formed by a white line and a traveling direction of an own vehicle.